A bonnet is one of the major components of certain types of valves. A valve is a device for controlling the flow or pressure of fluids such as liquids, gases, and slurries in a pipe or other enclosures. Control of flow uses a movable element that opens, shuts, or partially obstructs an opening in a passageway. There are a variety of valves in use, their classification is based on function, flow medium, mechanical design, method of operation, and motion of the parts within the valve relative to the valve seat and the manner in which the motion of the parts within the valve is produced. This invention applies to weir and radial style diaphragm valves because these are commonly used when sanitary, hygienic and sterile conditions are desired because the mechanism and the flow path are simple in construction and the working mechanical parts of the valve are isolated inside the bonnet, separated from the fluid flowing through the valve body of the valve. Weir diaphragm valve is also referred to here simply as weir valve and the radial style diaphragm valve is also referred to here simply as radial style valve. Hygienic has replaced the old nomenclature of sanitary in the industry but is being retained here for those in the art that are still using the term sanitary to mean hygienic. Hygienic is defined by BPE (Bio Process Equipment standard of the American Society of Mechanical Engineers) as pertaining to equipment and piping system that by design, material of construction and operation provide for the maintenance of cleanliness so that products produced by these systems will not adversely affect human or animal health. Other types of valve which are constructed differently from the weir or radial style valve described herein may not be able to apply the teachings of the claimed invention to maintain the valve in a hygienic condition. In a weir or radial style valve, a diaphragm, placed between the bonnet and valve body, separates the bonnet from the valve body. The process fluid or product flows through the passageway in the valve body and does not enter the bonnet. An actuator connected to a stem or spindle which is in communication with a handle for controlling the amount of pressure applied to the diaphragm is inside the bonnet compartment which is hollow. The diaphragm in the weir and radial style valves which is usually made of a flexible material is the movable element that opens, shuts, or partially obstructs an opening in a passageway where the fluid flows. The diaphragm is the part that gets in direct contact with the fluids. The actuator is the part that pushes the diaphragm against a weir on a weir valve or against an opening of the passageway on a radial style valve to partially close, close or stop the fluid flow. Fluid is allowed to flow when the diaphragm is not pressing fully on the weir or closing the fluid path. The actuator is also referred to in the field as the compressor. Herein, the actuator, spindle or stem, and the bonnet are collectively referred to as the bonnet assembly and the actuator connected to a spindle is referred to as actuator assembly which is also sometimes referred to as compressor device. The actuator assembly as stated above is situated within the bonnet which is a hollow housing. The components or parts of the components of the actuator responsible for the operation of the valve are housed inside the bonnet. Although it is only the diaphragm that gets direct contact with the fluid, for hygienic products regulated by agencies like the Food and Drug Administration, it is a common practice to clean the entire valve to prevent microbial build-up. There are no set cleaning schedules. This can be done after every usage or periodically at a given interval, mostly dictated by good manufacturing practices and the like. Most manufacturers, especially those that produce sanitary, hygienic or sterile products, have their own validated cleaning procedure. These valves are presently cleaned by dismantling the individual components of each part of the valve, the bonnet assembly further disassembled into its components, and subjecting these to a cleaning procedure. The cleaning procedure applied here is by submersion. Present valves and bonnet assemblies cleaned by submersion into the cleaning solution do not thoroughly clean the entire valve or the bonnet assembly. Dismantling is needed. Submersion also ruins the valve and its bonnet assembly because some or all parts of the present valves or bonnet assemblies are made of materials that are usually adversely affected by the cleaning solution. To prevent this, the cleaning process requires quite a bit of cleaning and rinsing solutions and is still without guaranty of being thoroughly cleaned because the present valves or bonnet assemblies are not properly designed to allow the cleaning solution to freely flow into, around the parts of the valve or the bonnet assembly, and exit out of the device while the valve or bonnet is submerged into the cleaning solution and in the subsequent rinsing solutions. Inadequate cleaning results when the cleaning solution is not free to flow in and out of the valve because some parts in the interior of the bonnet are not readily accessible, consequently, residual products or cleaning solutions still remain inside the bonnet compartment. Herein, cleaning solutions include other liquids such as the rinsing solutions even if it is not specifically stated. Looking at the main parts of a valve, cleaning the bonnet assembly would be the most tedious and time consuming. It is therefore desirable to design a bonnet assembly or an entire valve that can be cleaned by simply submerging the bonnet assembly or the entire valve into the cleaning solution without disassembly into its components or into parts of each components. Modification of the bonnet as described herein has allowed thorough cleaning of the whole weir diaphragm valve or the radial style diaphragm valve by submersion without dismantling the bonnet from the valve body or dismantling the bonnet into its parts.
The parts of the present valve that are not made of stainless steel, for example, the actuator and more specifically the spindle, is usually made of brass or bronze. With repeated usage, corrosion occurs on the spindle, particularly those that are threaded, due to the frictional rubbing between the spindle and the part of the actuator in direct communication or connected to the spindle, coupled with the chemical/s in the cleaning solution reacting with the brass and/or bronze material. Galling can also occur on assemblies that are manufactured entirely with stainless steel. Galling and corrosion combine to cause seizure especially on any threading mechanism employed in the valve thereby making the valve non-functional. Some valve manufacturers have substituted the brass and bronze material with stainless steel to prevent corrosion. This delays the process but does not solve the problem. The use of stainless steel for the spindle, with or without threading, requires a lubricant. This lubricant may not be compatible with the fluid being processed and in such situation may in itself be a contaminant. Further, the lubricant wears out with time. Also, the cleaning solution may react with the lubricant to cause its breakdown or crystallization which hastens the galling process.
It is therefore an object of this invention to provide a weir valve or a radial style valve having a bonnet assembly that will allow the whole valve to be thoroughly cleaned by submersion into a cleaning solution without dismantling the valve into its parts.
It is also an object of this invention to provide a method on how the bonnet can be redesigned on the various types of weir valve and radial style valves to allow cleaning without disassembly.
It is a further object of this invention to provide a spindle or stem and/or bonnet assembly or a valve as a whole made of a material that is not susceptible to galling and/or corrosion.